1. Field of the Invention
The invention relates to a wear-resistant material, a puffer cylinder, and a puffer-type gas circuit breaker, and in particular, to a wear-resistant material, a puffer cylinder, and a puffer-type gas circuit breaker, suitable for use in each one formed of pure aluminum or an aluminum alloy.
2. Description of the Related Art
In general, a puffer-type gas circuit breaker for electric power includes a stationary contactor, a movable contactor which is arranged capable of contacting with and separating from a stationary-side arc-contactor, a puffer cylinder linked with the movable contactor, a piston making a relative movement against the inner-wall surface of the puffer cylinder, a puffer chamber having a suction hole for sucking in the arc-extinguishable gas and a blast nozzle for spurting the same in the direction of the contactor, and a wearing on the outer periphery of the piston, slidably moving against the inner-wall surface of the puffer cylinder in a vessel filled up with an arc-extinguishable gas. The puffer-type gas circuit breaker is configured such that the arc-extinguishable gas spurted from the blast nozzle is sprayed to an arc which is generated by the separation of the stationary contactor and the movable contactor, and thereby the arc is extinguished.
With the puffer-type gas circuit breaker made up as above, an aluminum alloy is often used in the puffer cylinder for the purpose of reduction in weight. However, aluminum is easy to wear. Thus, various surface treatments are applied thereto in order to prevent the wear of a slidably-movable part.
In general, application of an alumite treatment, a plating treatment, or a variety of coatings are known in order to enhance the wear-resistance of an aluminum alloy.
There is, for example, a technique described in Patent Document 1 (JP-A-63-184223), as a technique for enhancement of the wear-resistance of an aluminum alloy. In this Patent Document 1, it is described that a puffer cylinder, an operation rod, and a presser plate are each formed of aluminum or an aluminum alloy, and an aluminum oxide coat formed by the alumite treatment is provided on respective portions of these components, coming in contact with each other.
Further, in Patent Document 2 (JP-A-2008-277014), it is described that a coating layer of an amorphous carbon or a diamond-like carbon, for use as material that is wear-resistant and low in frictional properties, is formed on a slidable surface of a seal-member made up of a synthetic rubber or fluororesin, for slidably supporting a seal-rod at a penetration part of a gas vessel, slidably moving against the seal rod, to thereby prevent an arc-extinguishable gas in the gas vessel from flowing out towards a manipulation-mechanism.
Still further, in Patent Document 3 (JP-A-2007-258137), it is described that a silicone grease having lubricity is applied to the outer peripheral surface of a cylinder slidably moving at a time when a stationary arc-contactor comes in contact with, or parts from a movable arc-contactor in order to reduce friction.
However, with the technique disclosed in Patent Document 1 described as above, the alumite treatment is applied to the respective portions of the puffer cylinder, the operation rod, and the presser plate, coming in contact with each other, and although an alumite coat formed by the alumite treatment is excellent in corrosion resistance and wear resistance, anodic oxidation is required in the alumite treatment, so that the cost of electric power required by facilities will increase, and in the case of using sulfuric acid, facilities for waste-water treatment will be required, thereby posing a cost problem.
Further, with the technique disclosed in Patent Document 2, the wear-resistance of a slidably-movable member is enhanced by coating with the material low in frictional properties such as the amorphous carbon or the diamond-like carbon, etc., however, these being the coating formed by the high-frequency plasma CVD (Chemical Vapor Deposition) method, if the method is to be applied to a puffer cylinder, a vacuum apparatus having a capacity capable of processing the puffer cylinder will be required.
Still Further, with the technique disclosed in Patent Document 3, because the silicone grease having lubricity is applied to the outer peripheral surface of the cylinder, serving as the slidably-movable part, there is the need for taking degradation of the silicone grease into consideration if the silicone grease is in use for a long time-period, thereby necessitating periodical maintenance.
The present invention has been developed in view of those points described as above, and it is therefore an object of the invention to provide a wear-resistant material, a puffer cylinder, and a puffer-type gas circuit breaker, available at a low cost, and excellent in wear-resistance.